Re: Spark Gaps (fwd)

---------- Forwarded message ----------
Date: Fri, 24 Apr 1998 06:13:49 +0000
From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Spark Gaps (fwd)

At 11:12 PM 4/22/98 -0600, you wrote:
>---------- Forwarded message ----------
>Date: Wed, 22 Apr 1998 09:48:52 +1200
>From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Re: Spark Gaps
>Hi John,
>> From:  John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
>> Sent:  Friday, April 17, 1998 7:09 PM
>> To:  Tesla List
>> Subject:  Re: Spark Gaps
>> >Not exactly sure what you mean. You can turn a transistor off any 
>> >time you like. I tried turning off at first primary energy notch,
>> >first primary quarter cycle (thank heavens for parasitic zeners in 
>> >the FETs), etc. It behaved just like a gap except it was a gap I 
>> >could effect ideal quench/dwell times with. The test setup was a 
>> >standard disruptive two coil system with k set to about 0.1
>> >
>> >Malcolm
>> >
>> -----------------------------------------------------
>>   Malcolm -
>>   I meant that because Tesla coils use dampened sine waves the quenching
>> would be different compared to quenching pulsed waves such as square waves.
>> Pulsed waves can have long off times where quenching would have no
>>   John Couture
>Just think of the transistors as a gap you can turn on and off any 
>time you like. The fact that waves are damped has no bearing on the 
>gap whatsoever. It reflects the fact that the coil operates on a 
>limited energy store. There was absolutely no difference between the 
>transistor setup and a standard disruptive setup save that the 
>primary ringdown was exponential due to the lack of the negative 
>resistance characteristic attributable to the airgap.

  Malcolm -

  It appears your tests were quenching pulsed or square waves and you
assumed this was the same as quenching dampened waves. I would expect the
quenching of the dampened waves would be different because of the
differences between sine waves and pulsed or square waves. 

  However, does it matter when the quench occurs if there is a spark from
the toroid? There would then be no energy left in the secondary to transfer
back to the primary. Quenching could occur at any time before the next bang.
There is a relatively long time between bangs. Your excellent waveform
photos show this very well.

  John Couture